What aspect do non-functional requirements assess in a system?

Non-functional requirements play a crucial role in evaluating the overall qualities and attributes of a system rather than its specific functionalities. They focus on how a system operates and the conditions under which it performs. This includes various operational criteria such as performance, reliability, scalability, usability, and security, which are essential for understanding the user experience and system effectiveness.

For instance, while functional requirements describe what the system should do (like processing orders), non-functional requirements address how well the system should perform these tasks (like completing an order in under five seconds). This distinction is vital for ensuring that a system meets user expectations and operational standards in real-world scenarios.

Focusing on operational criteria helps stakeholders understand the quality of service a system will provide, leading to better design and implementation choices.